Yikes! This doesn't really come across as a nice comment (bent minds???). There are good concrete reasons to pursue a PhD (ignoring soft reasons like pure interest): wanting a research career is one - it's pretty difficult to get hired as a scientist without a PhD. Also, historical evidence doesn't really support your claim that R&D is orthogonal to business value. Sure, pure science is often independent from $$$ (despite plenty of examples of producing real value), but applied R&D is oftentimes parallel to value generation. if R&D in general is useless, why do top tech companies spend big money on research groups?

Getting a PhD is a fine deal if you have good reasons.